Bolometric luminosity versus clump mass. The gray tracks indicate the evolutionary path through the diagram for the given initial masses as calculated by Molinari et al. (2008). The diagonal solid line marks the expected luminosity for a given mass for a zero-age main-sequence (ZAMS) star. The horizontal dashed line indicates the expected luminosity for a B2 star (~ 8M_⊙) as calculated by Mottram et al. (2011). The vertical dashed line marks the threshold calculated by Csengeri et al. (2014) above whichthe clumps are likely to host massive dense cores or a high-mass protostar. The dash-dotted lines are linear fits to the three evolutionary classes.